Technical Field
This disclosure relates to apparatuses and methods for embedding, encasing, encapsulating or covering fasteners in sealant, wherein the fasteners are disposed within a confined space.
Description of the Related Art
A typical aircraft wing assembly includes a central wing box and wings cantilevered from opposing sides of the wing box by “side of body joints.” The wings typically include interior spaces that serve as fuel tanks. Some of the metal fasteners that connect the outer skin of the wings to the central wing box or to the side of body joints also extend into the fuel tanks. To prevent an electrical discharge within such a fuel tank in the case of a lightning strike against the outer skin, aircraft manufacturers embed the portions of the fasteners that extend from the skin into the tank in an electrically insulating material or insulating sealant. However, because of the confined space in which the fasteners are disposed, embedding the portions of such fasteners that extend into the fuel tanks is problematic, labor intensive and often requires filling large portions of the side of body joints with insulating sealant, resulting in substantial added weight and increased fuel consumption.
Further, to reduce weight, composite materials are replacing metal as the material of construction of various aircraft components and structures, including the outer skin. Often, raw or uncoated edges of composite structures may be disposed in a confined space used to accommodate fuel. Because composite materials are conductive, any such raw edges also require insulation with a sealant, which is problematic because of the confined space.
Accordingly, a need exists for an improved device and method for embedding, covering, encasing or encapsulating fasteners, portions of fasteners and other structural elements that extend into confined spaces. This need applies to the aircraft industry and other industries as well.